1. Field of the Invention
The present invention relates to a supercharging device for compressing and forcibly supplying air to a combustion engine.
2. Description of Related Art
By way of example, in a motorcycle having a combustion engine equipped with a supercharger, a problem arises in efficiently arranging the supercharger, the air cleaner, the intake chamber and so on within a limited space available around the combustion engine. In view of this, the patent document 1 listed below suggests to position the carburetor and the air cleaner rearwardly of the forwardly tilted engine cylinder in a fashion juxtaposed relative to each other in a direction longitudinally of the motorcycle, to fluidly connect the air cleaner and the carburetor with each other through a suction passage and to place the supercharger in a space between the carburetor and the air cleaner.
[Prior Art Literature]
    [Patent Document] JP Laid-open Patent Publication No. H02-24282
According to the patent document 1 listed above, the space delimited between the carburetor and the air cleaner is utilized as a space for accommodating the supercharger and therefore, the supercharger can be reasonably arranged around the combustion engine with no problem. However, in this system disclosed in the patent document 1, an intake chamber (surge tank) is disposed on a discharge side of the supercharger and the intake chamber and the air cleaner are communicated with each other through a bypass passage, with a relief valve being disposed on the bypass passage for the discharge of a supercharged pressure therethrough. For this reason, a space for accommodating the bypass passage must be made available and therefore, the space cannot be said as efficiently utilized. Also, since the carbureter, the intake chamber and the air cleaner are disposed rearwardly of the engine cylinder in the order specified, an intake system unit, composed of those devices, tends to become bulky in a direction longitudinally of the motorcycle.